Optical device and method for obtaining reference planes, especially for hand-held tools

ABSTRACT

Method of direction control consisting in producing one or more parallel reference lines (7,8) that may be manipulated in such a way that their directions become parallel to the intended direction and with the help of plane mirrors making images (9,10) of the reference lines and images (12,13) of the object the straightening up of which is to be controlled. Implement for use at the method.

TECHNICAL FIELD

The invention relates to a method and device for controlling andmanipulating one or more parallel reference planes for use in thecontinuous alignment of hand-held tools.

BACKGROUND ART

When using hand-held drilling machines it is very difficult to see andcontrol the drilling direction. Thus the result often becomes more orless slanting holes that make mounting difficult and the result ugly.Also in other cases, as erecting posts, fences and door frames, bricklaying and similiar works problems of making the construction rightoccur. The problems are often of the art that one, for instance whendrilling, must be able to adjust the direction during ongoing operation.

The implements for direction control in use still to-day are mainly thesame as in older times and based upon set squares, plumb-lines, levelsand similiar utensils. The problems and detriments that accompany thoseprimitive methods are well known. They are useless for continouscontrol. They often demand helpers and do not give possibility ofcontrol in more than one direction.

SUMMARY OF THE INVENTION

The present invention is aimed at solving the problem and concerns a newprinciple to observe and with security continously control direction inmore than one plane, without eye movement, by using an optical system ofmutually parallel reference lines and two slanting, reflecting, planesurfaces.

The system does not require special lighting above the normal one andmay be designed either free-standing and independent of the machine usedor as an easily mount- and demount-able accessory part to the machine.It may be used not only for horisontal and vertical erections, but alsofor erections with arbitrary angles against the horisontal and verticalplanes. The optic is simple and does not contain any optically active,curved surfaces, i.e. no spherical lenses, spherical mirrors or likethings. It is in principle parallax-free and has modest demands on eyeposition, which otherwise can be a problem at the use of opticalsystems.

The method according to the invention implays producing one or more withthe intended direction parallell reference lines and letting thereference lines and the object, the direction of which is to becontrolled, be imaged in one or more plane reflecting surfaces.

Usually one wishes to control direction in more than one plane. For thisis needed at least two plane reflecting surfaces. To make it possible tosee, simultanously, the images in more than one reflecting surface thesurfaces have to form angles with each other. Further if one wishes tobe able to see the images from an eye position close behind for instancea drilling machine the reflecting surfaces have to be slanting. Thegreatest precision is obtained if the angle between the base lines ofthe reflecting surfaces is right or nearly right, but other angles maybe used if they from design or product technical reasons bringadvantages that surpass the relatively small loss of precision.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 and 2 show the principles of a device according to theinvention.

FIG. 3 is a sketch of the essential features of a preferred example ofthe invention.

FIG. 4 is an especially preferred design, where the implement has beendesigned with a corner piece (16) and provided with a backing band toeliminate visual disturbances from the environment.

FIG. 5 is an alternative design, which may be better from themanufacturing point of view, but less preferred, if the main aim ishighest possible precision.

FIG. 6 shows a preferred design that makes control at oblique directionpossible.

FIG. 7 shows a design of the implement according to FIG. 6 intended formounting at a hand-held drilling machine.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The example of the invention shown in FIG. 3 can be described as twounits (1) and (2) coupled, or able to be coupled, to each other at rightangle. The implement is placed on or attached to the actual surface withthe working point approximately symmetric between (1) and (2).

The essential elements of the units (1) and (2) consist of twotransparent screens (5) and (6) equipped with mutually parallellreference lines (7 and 8) at right angle against the long sides of thescreens. The screens are arranged perpendicularly against the base planeof the implement. Further two slanting (30°-60°, preferably 45°-50°angle) reflecting surfaces (3) and (4) are included.

To make explanation easier FIGS. 1 and 2 include an orthogonalcoordinate system with the origin at the working point and the axes x, yand z, where the x- and y-axes lay in and define the base plane and thez-axis represents the intended direction. FIG. 2 has for purposes ofvisuality a drill (11). When the rightening up is finished the drilldirection coincides with the z-axis. By comparision with FIG. 1 it isclear that in this situation the drill direction is correct, when aneye, placed behind or in front of the transparent screen (5) andobserving the reference lines (7) and the drill (11), sees the directionof the drill as parallell to the reference lines. The angle between thex-axis and the drill is then correct. At the same time information aboutthe angle between the y-axis and the drill is missing. This informationis obtained by the same procedure with respect to the screen (6) and thereference lines (8). To enable an operator to get simultanousinformation about the correctness of the angle between the x-axis andthe drill respectively the y-axis and the drill a system is needed thatcreates images of the drill and the reference lines and makes itpossible to look at those images simultanously. FIG. 2 shows such imagescreated by a system of slanting, plane mirrors giving virtual images(9,10) of the reference lines (7,8) in the base plane and virtual images(12,13) of the drill in a plane situated below the base plane.

As already mentioned the control device according to the invention maybe used for straightening up even at oblique angles to the workingplane. This may be done by using a non-orthogonal coordinate system i.e.slanting the reference lines in one or both planes. A more preferred wayis to use an orthogonal coordinate system i.e. to let the referencelines be perpendicular to the xy-plane and adjust the angle between itand the working surface.

A preferred design for straightening up at oblique angle to the workingplane is shown in FIG. 6 where (16) is a corner piece that with the aidof a post (18) is joined to a foot plate (19). Between the foot plate(19) and the corner piece (16) there is a knee joint (17). The kneejoint (17) can be adjusted to and locked into desired position. Forreasons of visuality the figure shows a hinge plane parallel to they,z-plane. Generally a positioning at a plane situated between the y,z-and x,z-planes, for instance a plane through their intersection, mightbe preferred. By the appropriate design of the post (18) and the cornerpiece (16), for instance an octagonal post and the correspondingpassage, the hinge plane can easily be adapted to, for each application,the appropriate place. In some cases there may be need for increasingrespectively decreasing the height of the post between the joint and thecorner piece. An appropriate way of doing this is to let the post passthe corner piece and equip the unit with suitable devices for fixing atdesired levels.

In the design according to FIG. 7 the post (18) has been elongated andequipped with a steering (20) that via a cuff (21) has been fastened tothe neck of the drilling machine (23). The steering keeps the postparallel to the axis of the drilling machine. Inside the steering thepost is easily movable in axial direction. The upper end of the post isloaded by a spring (22). Between the steering (20) and the corner piece(16) the post (18) is provided with an easily movable ball joint (24).The extent of the ball joint's movements is normally situated within aswivel area of about 30°. The ball joint causes the whole foot plate tomake contact with the ground surface, when the operator presses themachine against it. With the aid of the mirrors the operator can easilyadjust any misdirection of the machine. The device may be designed insuch a way that it is indicating drilling depth and thus replaces thedepth indicators that are common on modern drilling machines. The holderthat fixes the steering may be designed with a handle which provides atwo-hand grip to the drilling machine.

The number of reference lines may be limited to just one. For thestraightening up of posts, brick laying etc this reference line may beconstituted of a hanging plumb-line and be part of a preferredembodiment of the invention.

At drilling etc. the use of just one reference line puts greater demandsupon the orientation of the implement. A relatively large number ofreference lines distributed in two planes that form right or nearlyright angle to each other is preferred. The mutual distance and thelength of the reference lines is adapted to the dimensions of thecontrolled object. The length of the planes is adapted to the need offree working space between the working point and the control implement.

The reference lines may be constituted of etched lines on transparentplates, but also of for instance a system with sticks designed as acomb. The lines may be made in ways other than etching. For verticalrightening ups an interesting alternative may be a system of plumb-linesor freely suspended bars. A number of other possibilities besides thementioned would be obvious to a man of the art.

Specially preferred designs include, beside reference line system andimage producing means, a back shield to eliminate disturbing visualimpressions from the environment that often may be very unruly. Such ashield is shown in FIG. 4, where the back shield is constituted of aneasily flexible band (14) of metal or plastic with anchoring points atthe ends of the units (1,2). A number of other possibilities would beobvious to a man of the art.

As the illumination conditions may be bad at places, where the implementis used, the design should be done in such a way that the referencelines and by means of this the reference line images get good contrastwith the background. This may be done among other ways by the choice ofcolor. Concerning transparent plates with etched lines the same effectmay be obtained by giving the material different translucent properties.

A preferred device according to the invention meant for drillingconsists of two angled planes with reference lines together with twooblique reflecting surfaces joined to the reference line planes. Andevice for sawing with for instance an electric circle saw may beconstituted of the above mentioned components and beside that areflecting surface applied at the saw blade.

The implement can be made of a number of different materials. Concerningsmaller units, meant for instance for drilling, production by thecasting of plastic of optical quality is an interesting alternative. Onecan then, by appropriate choice of angles, in order to get totalreflexion, avoid the need of special preparation to make the surfacesreflecting.

For plastic casting it may be preferable to increase the number ofplanes in such a way that one obtains a horse shoe shaped design withmore than two reference line planes.

If a design according to FIG. 3 is chosen the units (1,2) can be madefoldable. This will reduce the need for space at storing between uses.The foldability may be achieved in several different ways. A simple,preferred way is to make the units joined to each other by appropiatedesign of the combining piece.

I claim:
 1. A method for providing direction control to a hand held toolwhich comprises:establishing, independently of the tool, one or morereference lines parallel to an intended working direction of the tool;establishing images of the reference line or lines and of the tool; andaligning the image of the tool to the images of the reference line orlines to provide direction control to the tool.
 2. The method of claim 1wherein the images are established upon a reflecting surface which ispositioned at an angle to the reference line or lines.
 3. The method ofclaim 1 wherein the images are established on first and secondreflecting surfaces which are positioned at an angle to the referenceline or lines, wherein the first reflecting surface is positioned at anangle to the second reflecting surface.
 4. The method of claim 3 whichfurther comprises selecting the angle between the first and secondreflecting surfaces to be substantially 90°.
 5. The method of claim 2wherein a plurality of reference lines are established upon at least onetransparent surface positioned at an angle to the reflecting surface. 6.A device for providing direction control to a hand held tool whichcomprises:means for establishing, independently of the tool, one or morereference lines parallel to an intended working direction of the tool;and means for establishing images of the reference line or lines and ofthe tool; wherein the images of the tool can be aligned to the images ofthe reference line or lines to provide direction control for the tool.7. The device of claim 6 wherein the means for establishing referencelines comprises a transparent plate which includes a plurality ofparallel reference lines.
 8. The device of claim 7 wherein the means forestablishing images comprises a reflecting surface oriented at an angleto the transparent plate.
 9. The device of claim 6 wherein the means forestablishing reference lines comprises first and second transparentplates positioned and oriented at an angle to each other, each plateincluding a plurality of parallel reference lines.
 10. The device ofclaim 9 wherein the means for establishing images comprises first andsecond reflecting surfaces positioned and oriented at an angle to thefirst and second transparent plates, respectively.
 11. The device ofclaim 10 wherein each reflection surface is joined to the transparentplate at a base line, with the base line of the first transparent platepositioned at an angle with respect to that of the second transparentplate.
 12. The device of claim 11 wherein the angle between the firstand second transparent plates is substantially 90°.
 13. The device ofclaim 6 which further comprises a post for holding both said referenceline establishing means and image establishing means; a foot forengaging a work surface; and a joint connecting the foot to the post toallow rotational movement therebetween.
 14. The device of claim 13wherein the post further includes a holder for engaging the tool and aball joint connecting the holder to the post to allow rotationalmovement therebetween.
 15. The device of claim 6 wherein the referenceline(s) are provided by one of plumb-line(s), bar(s), string(s) arrangedin a frame, or a comb structure.